Question 1 of 33

1. What is the purpose of PROG/DATA button in BOP of AC drive?

To store the entered data and factory stored data

To change the parameter setting

To display the data status of frequency and current

To display the data direction of rotation forward/REV

Question 1 of 33

Question 2 of 33

2. How can constant torque be obtained from armature and field controlled drives?

By reducing the field current

By controlling the armature voltage

By reducing the armature current

By increasing the field current

Question 2 of 33

Question 3 of 33

3. Which is the correct sequence operation of key button in BOP of AC drive to change the direction of rotation?

Press OFF → REV → ON

Press ON → OFF → REV → ON

Press ON → REV → OFF → ON

Press ON → REV → ON

Question 3 of 33

Question 4 of 33

4. What is the function of power controller in drive circuits?

It detects the overloading condition of motor

It maintain the torque at low voltage conditions

It sounds an alarm in no load conditions

It reduce motor current during transient operation

Question 4 of 33

Question 5 of 33

5. Which is proportional to the torque in D.C motor?

Armature current

Back e.m.f

Field current

Terminal voltage

Question 5 of 33

Question 6 of 33

6. What is the function of Field Supply Unit (FSU) in DC drive?

Provides a constant voltage to the field winding of motor

Provides variable voltage to the field winding of motor

Provides a constant voltage to the armature of the motor

Produces required firing current to the firing circuit

Question 6 of 33

Question 7 of 33

7. What is the purpose of LCD in Basic Operator Panel (BOP) in AC drive?

Monitor the parameter of AC drive

Indicate the status of drive

Indicate the incorrect operation of BOP

Indicate the display error in reading

Question 7 of 33

Question 8 of 33

8. What is the advantage of AC drive compared to DC drive?

Power circuit and control circuits are simple

Fast response and wide speed range of control

Installation and running cost is less

Requires less space

Question 8 of 33

Question 9 of 33

9. What is the reason for using shielded cable for connecting low level signal circuits in DC drives?

Eliminates the electrical interference

Good appearance

Easy for connection

Protects from mechanical injuries

Question 9 of 33

Question 10 of 33

10. What is the purpose of LCD on basic operator panel in D.C drive?

Monitor the parameter

Display availability of supply

Indicate the fault

Display the speed

Question 10 of 33

Question 11 of 33

11. What is the main use of A.C drive?

Control stepless speed in motors

High starting torque

Group drive motors

Interlocking system in industries

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Question 12 of 33

12. Which type of sensing unit is employed in drive systems?

Resistance temperature detector

Speed sensing

Opto coupler

Photo voltaic cell

Question 12 of 33

Question 13 of 33

13. What is the disadvantage of DC drive?

More expensive than AC drive for high capacity motor

Not suitable for high speed operation

More complex with a single power conversion

Installation of DC drives is more complicated

Question 13 of 33

Question 14 of 33

14. How can the base speed of D.C shunt motor be increased by using D.C drive?

By increasing the supply voltage

By increasing the field current

By reducing the field current

By reducing the armature voltage

Question 14 of 33

Question 15 of 33

15. What is the full form of B.O.P in D.C drive?

Bridge Operator Programme

Basic Operational Panel

Bridge Operation Panel

Basic Operation Programme

Question 15 of 33

Question 16 of 33

16. Why is it necessary to keep V/F ratio constant in a drive?

Maintain the rated torque at all speeds

Maintain the speed of motor constant

Keep the stator flux maximum

Maintain the rotor current minimum

Question 16 of 33

Question 17 of 33

17. Which is the classification of drive according to dynamics and transients?

Short time duty drive

Automatic control drive

Intermittent duty drive

Variable position control drive

Question 17 of 33

Question 18 of 33

18. What is the name of the characteristic curve in D.C drive?

Speed Vs torque characteristic

Torque Vs field current characteristic

Speed Vs armature current characteristic

Field current Vs armature current characteristic

Question 18 of 33

Question 19 of 33

19. What is electric drive?

A machine converts mechanical energy into electrical

A device converts A.C to D.C supply

A device used as prime mover for generator

An electro mechanical device for controlling motor

Question 19 of 33

Question 20 of 33

20. Which type of machine in industries is provided with multi-motor electric drive?

Shearing machine

Rolling machine

Heavy duty electric drilling machine

Air Compressor

Question 20 of 33

Question 21 of 33

21. Which is the application of single quadrant loads operating in first quadrant in drives?

Centrifugal pumps

Hoists

Elevators

Conveyors

Question 21 of 33

Question 22 of 33

22. Which device controls the speed of A.C motor in A.C drive?

Field supply unit (FSU)

COMMS technology box

Microprocessor based electronic device

Speed feedback technology box

Question 22 of 33

Question 23 of 33

23. What is IGBT in VF drive?

Inverter switching device

Field supply switching device

D.C bus switching device

Rectifier switching device

Question 23 of 33

Question 24 of 33

24. Which power modulator is used in the electric drive system?

Phase sequence indicator

Cyclo converters

Servo controlled voltage stabilizer

Frequency multiplier

Question 24 of 33

Question 25 of 33

25. Which control system consumes very low power for motion control in AC and DC motors?

Field control

Armature control

Voltage control

Drives control

Question 25 of 33

Question 26 of 33

26. What is the function of IGBT in AC drive?

Smoothening incoming A.C supply

Stabilize the output voltage from the rectifier

Converts incoming A.C power into D.C power output

Controls the power delivered to the motor

Question 26 of 33

Question 27 of 33

27. What is the function of VSI drives?

Converts A.C to D.C

Converts A.C to A.C

Converts D.C to D.C

Converts D.C to A.C

Question 27 of 33

Question 28 of 33

28. What is the purpose of JOG key in control panel of D.C drive?

Inching operation

Reverse the direction of motor

Restart the motor

Stop the motor

Question 28 of 33

Question 29 of 33

29. What is the name of the component marked as 'X' in the block diagram of AC drive?

Rectifier

D.C bus

Inverter

A.C motor

Question 29 of 33

Question 30 of 33

30. Which control system is used for Eddy current drives?

Rectifier controller

DC chopper controller

Slip controller

AC voltage controller

Question 30 of 33

Question 31 of 33

31. Why are A.C drives better suited for high speed operation?

No brushes and commutation

High starting torque

Having lighter gauge winding

Robust in construction

Question 31 of 33

Question 32 of 33

32. Which drive is classified according to mode of operation?

Continuous duty drive

Group drive

Manual drive

Individual drive

Question 32 of 33

Question 33 of 33

33. Why are A.C drives mostly used in process plants?

Robust in construction

Easy to operate

Very high starting torque

Maintenance free long life

Question 33 of 33